#include <string.h>
#include <stdio.h>
#include "des.h"

typedef char ElemType;

/* ��ʼ�û���IP */

const static char IP_Table[64] =
{
    57,49,41,33,25,17,9,1,
    59,51,43,35,27,19,11,3,
    61,53,45,37,29,21,13,5,
    63,55,47,39,31,23,15,7,
    56,48,40,32,24,16,8,0,
    58,50,42,34,26,18,10,2,
    60,52,44,36,28,20,12,4,
    62,54,46,38,30,22,14,6
};

/* ���ʼ�û���IP^-1 */
const static char IP_1_Table[64] =
{
    39,7,47,15,55,23,63,31,
    38,6,46,14,54,22,62,30,
    37,5,45,13,53,21,61,29,
    36,4,44,12,52,20,60,28,
    35,3,43,11,51,19,59,27,
    34,2,42,10,50,18,58,26,
    33,1,41,9,49,17,57,25,
    32,0,40,8,48,16,56,24
};

/* �����û���E */
const static char E_Table[48] =
{
    31, 0, 1, 2, 3, 4,
    3, 4, 5, 6, 7, 8,
    7, 8,9,10,11,12,
    11,12,13,14,15,16,
    15,16,17,18,19,20,
    19,20,21,22,23,24,
    23,24,25,26,27,28,
    27,28,29,30,31, 0
};

/* �û�����P */
const static char P_Table[32] =
{
    15,6,19,20,28,11,27,16,
    0,14,22,25,4,17,30,9,
    1,7,23,13,31,26,2,8,
    18,12,29,5,21,10,3,24
};

/* S�� */
const static char S[8][4][16] =
{
    /* S1 */
    {
        {14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
        {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
        {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
        {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}
    },

    /* S2 */
    {
        {15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
        {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
        {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
        {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}
    },

    /* S3 */
    {
        {10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
        {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
        {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
        {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}
    },

    /* S4 */
    {
        {7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
        {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
        {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
        {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}
    },

    /* S5 */
    {
        {2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
        {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
        {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
        {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}
    },

    /* S6 */
    {
        {12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
        {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
        {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
        {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}
    },

    /* S7 */
    {
        {4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
        {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
        {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
        {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}
    },

    /* S8 */
    {
        {13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
        {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
        {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
        {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
    }
};

/* �û�ѡ��1 */
const static char PC_1[56] =
{
    56,48,40,32,24,16,8,
    0,57,49,41,33,25,17,
    9,1,58,50,42,34,26,
    18,10,2,59,51,43,35,
    62,54,46,38,30,22,14,
    6,61,53,45,37,29,21,
    13,5,60,52,44,36,28,
    20,12,4,27,19,11,3
};

/* �û�ѡ��2 */
const static char PC_2[48] =
{
    13,16,10,23,0,4,2,27,
    14,5,20,9,22,18,11,3,
    25,7,15,6,26,19,12,1,
    40,51,30,36,46,54,29,39,
    50,44,32,46,43,48,38,55,
    33,52,45,41,49,35,28,31
};

/* �����ƴ���Ĺ涨 */
const static char MOVE_TIMES[16] =
{
    1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};

static void ByteToBit(ElemType ch,ElemType bit[8]);
static void BitToByte(ElemType bit[8],ElemType *ch);
static void Char8ToBit64(const ElemType ch[8],ElemType bit[64]);
static void Bit64ToChar8(ElemType bit[64],ElemType ch[8]);
static void DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]);
static void DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]);
static void DES_ROL(ElemType data[56], int time);
static void DES_IP_Transform(ElemType data[64]);
static void DES_IP_1_Transform(ElemType data[64]);
static void DES_E_Transform(ElemType data[48]);
static void DES_P_Transform(ElemType data[32]);
static void DES_SBOX(ElemType data[48]);
static void DES_XOR(ElemType R[48], ElemType L[48],int count);
static void DES_Swap(ElemType left[32],ElemType right[32]);

/* �ֽ�ת���ɶ����� */
static void ByteToBit(ElemType ch, ElemType bit[8])
{
    int cnt;

    for(cnt = 0; cnt < 8; cnt++)
    {
        *(bit+cnt) = (ch>>cnt)&1;
    }
}

/* ������ת�����ֽ� */
static void BitToByte(ElemType bit[8], ElemType *ch)
{
    int cnt;

    for(cnt = 0; cnt < 8; cnt++)
    {
        *ch |= *(bit + cnt) << cnt;
    }
}

/* ������Ϊ8���ַ�תΪ������λ�� */
static void Char8ToBit64(const ElemType ch[8],ElemType bit[64])
{
    int cnt;

    for(cnt = 0; cnt < 8; cnt++)
    {
        ByteToBit(*(ch + cnt), bit + (cnt << 3));
    }
}

/* ��������λ��תΪ����Ϊ8���ַ� */
static void Bit64ToChar8(ElemType bit[64], ElemType ch[8])
{
    int cnt;

    memset(ch, 0, 8);

    for(cnt = 0; cnt < 8; cnt++)
    {
        BitToByte(bit+(cnt<<3),ch+cnt);
    }
}

/* ��Կ�û�1 */
static void  DES_PC1_Transform(ElemType key[64], ElemType tempbts[56])
{
    int cnt;

    for(cnt = 0; cnt < 56; cnt++)
    {
        tempbts[cnt] = key[(int)PC_1[cnt]];
    }
}

/* ��Կ�û�2 */
static void  DES_PC2_Transform(ElemType key[56], ElemType tempbts[48])
{
    int cnt;

    for(cnt = 0; cnt < 48; cnt++)
    {
        tempbts[cnt] = key[(int)PC_2[cnt]];
    }
}

/* ѭ������ */
static void DES_ROL(ElemType data[56], int time)
{
    ElemType temp[56];

    /* ���潫Ҫѭ���ƶ����ұߵ�λ */
    memcpy(temp, data, time);
    memcpy(temp + time, data + 28, time);

    /* ǰ28λ�ƶ� */
    memcpy(data, data + time, 28 - time);
    memcpy(data + 28 - time, temp, time);
    /* ��28λ�ƶ� */
    memcpy(data + 28, data + 28 + time, 28 - time);
    memcpy(data + 56 - time, temp + time, time);
}

/* IP�û� */
static void DES_IP_Transform(ElemType data[64])
{
    int cnt;
    ElemType temp[64];

    for(cnt = 0; cnt < 64; cnt++)
    {
        temp[cnt] = data[(int)IP_Table[cnt]];
    }

    memcpy(data, temp, 64);
}

/* IP���û� */
static void DES_IP_1_Transform(ElemType data[64])
{
    int cnt;
    ElemType temp[64];

    for(cnt = 0; cnt < 64; cnt++)
    {
        temp[cnt] = data[(int)IP_1_Table[cnt]];
    }

    memcpy(data, temp, 64);
}

/* ��չ�û� */
static void DES_E_Transform(ElemType data[48])
{
    int cnt;
    ElemType temp[48];

    for(cnt = 0; cnt < 48; cnt++)
    {
        temp[cnt] = data[(int)E_Table[cnt]];
    }

    memcpy(data, temp, 48);
}

/* P�û� */
static void DES_P_Transform(ElemType data[32])
{
    int cnt;
    ElemType temp[32];

    for(cnt = 0; cnt < 32; cnt++)
    {
        temp[cnt] = data[(int)P_Table[cnt]];
    }

    memcpy(data, temp, 32);
}

/* ��� */
static void DES_XOR(ElemType R[48], ElemType L[48] , int count)
{
    int cnt;

    for(cnt = 0; cnt < count; cnt++)
    {
        R[cnt] ^= L[cnt];
    }
}

/* S���û� */
static void DES_SBOX(ElemType data[48])
{
    int cnt;
    int line, row, output;
    int cur1, cur2;

    for(cnt = 0; cnt < 8; cnt++)
    {
        cur1 = cnt * 6;
        cur2 = cnt << 2;

        /* ������S���е������� */
        line = (data[cur1] << 1) + data[cur1 + 5];
        row = (data[cur1 + 1] << 3) + (data[cur1 + 2] << 2)
              + (data[cur1+3] << 1) + data[cur1 + 4];

        output = S[cnt][line][row];
        /* ��Ϊ2���� */
        data[cur2] = (output&0X08) >> 3;
        data[cur2+1] = (output&0X04) >> 2;
        data[cur2+2] = (output&0X02) >> 1;
        data[cur2+3] = output&0x01;
    }
}

/* ���� */
static void DES_Swap(ElemType left[32], ElemType right[32])
{
    ElemType temp[32];

    memcpy(temp, left, 32);
    memcpy(left, right, 32);
    memcpy(right, temp, 32);
}

/* �������Կ */
void DES_MakeSubKey(const char key[8], subkey_t subKey)
{
    ElemType bKey[64];
    ElemType temp[56];
    int cnt;

    /* ����Կת��Ϊ������ */
    Char8ToBit64(key, bKey);
    /* �������Կ */
    DES_PC1_Transform(bKey, temp);/* PC1�û� */

    for(cnt = 0; cnt < 16; cnt++) /* 16�ֵ�����16������Կ */
    {
        DES_ROL(temp, MOVE_TIMES[cnt]);/* ѭ������ */
        DES_PC2_Transform(temp, subKey[cnt]);/* PC2�û�����������Կ */
    }
}

void DES_DoWork(const char in[8], char out[8], subkey_t subKey, choose_t Mode)
{
    ElemType Bits[64];
    ElemType copyRight[48];
    int cnt;

    Char8ToBit64(in, Bits);
    /* ��ʼ�û���IP�û��� */
    DES_IP_Transform(Bits);

    if (Mode == ENCRYPT)
    {
        /* 16�ֵ�� */
        for(cnt = 0; cnt < 16; cnt++)
        {
            memcpy(copyRight, Bits + 32, 32);
            /* ���Ұ벿�ֽ�����չ�û�����32λ��չ��48λ */
            DES_E_Transform(copyRight);
            /* ���Ұ벿��������Կ���������� */
            DES_XOR(copyRight, subKey[cnt], 48);
            /* ��������S�У����32λ��� */
            DES_SBOX(copyRight);
            /* P�û� */
            DES_P_Transform(copyRight);
            /* ��������벿�����Ұ벿�ֽ������ */
            DES_XOR(Bits, copyRight, 32);

            if(cnt != 15)
            {
                /* ����������Ҳ��Ľ��� */
                DES_Swap(Bits, Bits + 32);
            }
        }
    }
    else
    {
        /* 16�ֵ�� */
        for(cnt = 15; cnt >= 0; cnt--)
        {
            memcpy(copyRight, Bits + 32, 32);

            /* ���Ұ벿�ֽ�����չ�û�����32λ��չ��48λ */
            DES_E_Transform(copyRight);

            /* ���Ұ벿��������Կ���������� */
            DES_XOR(copyRight, subKey[cnt], 48);

            /* ��������S�У����32λ��� */
            DES_SBOX(copyRight);

            /* P�û� */
            DES_P_Transform(copyRight);

            /* ��������벿�����Ұ벿�ֽ������ */
            DES_XOR(Bits, copyRight, 32);

            if(cnt != 0)
            {
                /* ����������Ҳ��Ľ��� */
                DES_Swap(Bits, Bits + 32);
            }
        }
    }

    /* ���ʼ�û���IP^1�û��� */
    DES_IP_1_Transform(Bits);
    Bit64ToChar8(Bits, out);
}
